Photo: NBC

Before the contestants for "The Biggest Loser" even got to the ranch for Episode 1, they were hauled off the bus and told to run a mile -- in the sand! That's quite a welcome! The fastest time was 14:17, and the slowest time was 27:47. Contestants struggled through the sand and also struggled for what was probably the first consistent cardio they had done in a long time, except for Daniel, of course, who is continuing from Season 7 and won handily. The end result: Two contestants gasping for air in the medic tent, two other contestants medi-vaced to the hospital and everybody else with a pretty sobering glimpse into what the next few weeks and months were going to be like.

So what actually happens when a morbidly-obese person decides to run? The two big things are: 1) the extra weight greatly impacts the joints and 2) the cardiovascular system is put to the ultimate test.

"I told my wife," said Dr. Darrin Bright, a sports medicine physician and Medical Director of the Columbus Marathon, "It's like running in sand carrying me on your back!" Bright cautions, "I'm sure they had medical clearance to participate in the run, but for any event you have to train properly." Bright suggested that a walking routine would have been a much better place to start with these contestants.

It's certainly true that the more you weigh, the harder you have to work. I did a quick comparison by weight of an individual running for 20 minutes at a 12-minute mile pace. (The calculator considered everything slower than 12 minutes to be walking, natch). Here are the results:

• A 150-pound person burns 190 calories.
• A 250-pound person burns 318 calories (there are four contestants in the 250-pound range).
• A 425-pound person burns 540 calories! (there are five contestants over 400 pounds).

The difference in effort is significant, no wonder four of them barely made it across the finish line!

As for your joints, "the rule of thumb is that walking puts three pounds of joint reactive stress for every 10 pounds you weigh for walking," said Dr. Alex Glogau, senior partner at Associated Orthopedics and Sports Medicine and adjunct clinical professor at UT Southwestern. "For an average weight person that's 100 to 200 pounds of force from walking, for those contestants it could be 300 to 600 pounds. With running the stress factor goes up to 4 to 5 pounds."

If you are overweight and want to start a running program, there are some ways to avoid injury.

1. See your doctor and get clearance. All of the Biggest Loser contestants had rigorous medical tests before they began training at the ranch. Even then there were some problems. Make sure you get a doctor's OK, and follow his recommendations.
2. Start at the appropriate level for you. Dr. Glogau suggests a morbidly-obese person begin on a recumbent bike and then progress from a walking program into a running program. If you haven't run in a while, start by doing a walk/run. Walk for 30 minutes, but throw in three or four one-minute bursts of running. Add a minute or two of running per week until you get to a full 30-minute jog.
   
3. Make sure you have good shoes. Invest in a good pair of sneakers, and make sure they have a stabilizing sole. I recommend that you go to a local running store where they can properly fit you to the right shoe. The folks at the big box stores will have no idea how to help you.
4. Run on a proper surface. If your town has a local running track, that would be ideal. Both pavement and concrete are very hard surfaces that could leave you with injuries. It's best if you can run on the shoulder of the road on the packed dirt, or find some trails near your home.

The key to beginning any training program is to think about progression. You want to start with simple, easy moves and gradually make them tougher. This is the smart way to lose weight and avoid injury.

Before you watch this week's installment of "The Biggest Loser," here's a recap of Episode 1.